Tuesday, September 26, 2006

South Africa's shark attacks have no pattern

Of the 99 Great White shark attacks worldwide since 1990, nearly half have occurred in South Africa.But experts say no patterns have emerged in the South African attacks, nor can they say what caused the sharks to attack.

This emerged from a study by shark scientist Geremy Cliff of the Natal Sharks Board, whose findings were published in Finding A Balance, a collection of specialist reports designed to inform the City of Cape Town on strategies to deal with shark conservation and recreational safety.Cliff said that worldwide, the 1990s had seen the highest number of shark attacks of any decade, and that the trend appeared to be continuing.

'Great White sharks are the culprits in almost all cases'Although the number of attacks was increasing globally, the number of deaths had dropped from 13 percent in the 1990s to eight percent this decade, which was attributed to advances in safety practices and medical treatment, and a more aware public avoiding "potentially dangerous situations".Most shark attacks occurred in the US, particularly Florida, and in 2005 surfers and boardriders made up 54 percent of the victims worldwide, swimmers 37 percent and divers five percent, Cliff said.

In the Cape Peninsula there have been 28 documented shark attacks since 1960.Cliff said there appeared to be "no causative factors" for the attacks."Great White sharks are the culprits in almost all cases, while spearfishermen represent the group that are at greatest risk," he wrote.Spearfishermen ventured far offshore, spent several hours in water up to 30m deep, mostly at the surface where they were "highly conspicuous silhouettes, and handle bleeding and struggling fish, which are highly attractive to sharks".

Scuba divers were a low-risk group because they were generally in large numbers and generated a lot of noise."Despite the low numbers - including 26 years in which there were no incidents at all, and a possible under-reporting in the early years - the number of incidents per decade has increased steadily from one in the 1960s (0.1 a year), to eight in the current decade (1.3 a year)," Cliff wrote.This could be attributed to the increased number of people using the sea for recreation nationally.

Although there were only four fatalities, it was "noteworthy" that three of them occurred in the last four years.Although the shark attack files were started in the 1960s, there were nine recorded cases of shark attacks in the peninsula from 1900 to 1959, of which four were fatal.Water turbidity (cloudiness) did not appear to play a role. Only one of the 21 attacks where water depth was estimated had occurred in shallow water. The average depth was six metres and average distance offshore was 100m.Potentially valuable information, like the presence of seals or fishing activity, was not recorded.


Post a Comment

<< Home